This invention relates generally to the field of ring support structures for lift cranes and, more particularly, to improved connections between the ring segments which form the ring support structures.
The load lifting capabilities of cranes have been increased by the development and use of crane support rings. By distributing the weight of a crane and its load over a large surface area, the support ring stabilizes the crane and increases the lift capacity thereof. The support ring is usually supported above the ground by timber blocks wedged between the support ring and the ground or by jacks intervally positioned along the perimeter of the ring.
Since crane support rings are typically large (60 ft. diameter rings are common), the tings must often be disassembled for transport to other jobsites, positioning of liftcranes, storage, etc. Therefore, support rings typically are comprised of a number of ring segments which are connected together to form the support ring. Because the ring segments are frequently connected and disconnected, a ring segment connection allowing rapid and simple assembly of the ring segments is desirable.
As is well known in the art, ring segments are usually connected by means of bolt connectors. For example, U.S. Pat. No. 4,579,234 to Delago et al. discloses that the horizontal, overlapping flanges of adjacent ends of two ring segments may be bolted together. Typically, to insure the structural integrity of the support ring, many bolts, e.g., 6, 8 or 10, are used to interconnect the ring segments. While the use of bolt connectors provides satisfactory results, removing the large number of bolts to disconnect the ring segments, and then performing the opposite task to assemble the ring, is time-consuming and inefficient.